May I know what does "mass of flour left" mean ?

Question

Betty had 3/4 kg of flour. She used 1/4 kg of it to make a cake. What was the mass of flour left in grams?

Answer 1

3/4 kg - 1/4 kg = (3-1)/4 = 2/4 = 1/2 kg = 0.5 kg = 500 grams

one kilogram =1,000 grams, half a thousand grams = 1000/2 = 500 grams

"kilo" means a thousand, similar to a kilometer = 1,000 meters

1 kg = 1,000 g

1 km = 1,000 m